Preserving History—and Lives
Meshing fire safety and preservation goals in historic structures is a challenge for engineering firms
As America enters a new century, its citizens are gaining renewed appreciation for the architectural heritage of an earlier era. From glittering beaux arts train stations to cultural landmarks like Radio City Music Hall and Detroit Symphony Orchestra Hall, inspirational stories of structures being rescued and returned to their former glory generate excitement and warm the heart.
Architectural history reminds us that these structures were special in their day, heralded as landmarks of design and functionality. Over the years, however, many buildings saw their beauty fade as they were converted to alternative uses or 'remodeled' beyond recognition. Yet, even in decline, they continued to inspire feelings of pride and loyalty in their communities.
The rebirth of interest in America's architectural gems could not have come soon enough. It is estimated that fewer than 10 percent of all buildings across the country were constructed prior to 1940 and, not surprisingly, that percentage continues to fall. Not only is the protection and revitalization of our historic structures critically important from the perspective of preservation, but it has also become pivotal to the economic development of urban areas, as these efforts form the centerpiece of many community revitalization plans.
A major challenge is to find ways for historical structures to become economically viable but still conform to modern needs and expectations. Today, who would design a hotel with the cramped rooms that were standard in pre-World War II America? Massive open staircases and common areas are magnificent to behold . yet fail to conform to either the letter or spirit of today's safety codes. The challenges of balancing needs and expectations require the coordinated effort of public officials, private developers, architects, remodelers and safety officials to ensure that renovated structures meet the requirements of today's marketplace.
Safety first for midshipmen
Of particular importance is ensuring fire safety in historical structures. Practically no pre-World War II design would conform to today's code requirements. As a result, fire safety is usually front and center in renovation projects.
A recent example was the renovation of Bancroft Hall at the U.S. Naval Academy, Annapolis, Md. This 11-building complex, constructed over a period of 56 years beginning in 1904, is one of the largest dormitories in the world. Covering 1.4-million square feet, it contains over 1,800 dormitory rooms on its upper floors. On the lower floors, numerous special-purpose spaces exist, including a drill hall, a theater and various athletic facilities.
The lower floors interconnect, and these spaces have large occupancy loads with few exits. The key to the project was to create horizontal exits from building to building-as well as conventional exits-which together would meet the spirit, if not the letter of the fire codes. The engineering team conducted smoke-modeling analyses to determine the solutions, which included fire doors and fire walls.
As for the second-floor dormitory areas, the problem was long hallways without egress points. Working with architecture/engineering firm RTKL Associates, Baltimore, fire-protection consultants came up with several solutions that worked well together. First, suites of rooms were located at the ends of corridors, which resulted in shorter corridors and reduced smoke and fire hazards. In other areas, the design team added interior stairwells, which solved egress problems without altering the appearance of the building's exterior.
The Toyon Hall dormitory renovation at Stanford University, Palo Alto, Calif., posed a different series of problems. Originally constructed in 1921, this landmark structure required a seismic upgrade. In addition to having traditional central corridors with rooms, Toyon Hall features a 500-seat assembly hall with a high ceiling and attached mezzanine. There were critical openings between three floor levels, and only one code-conforming exit on the third floor. One third-floor egress even went through a student's room window to reach the fire-escape.
Working closely with the Palo Alto-based architectural firm of Cody Anderson Wasney to enhance the fire safety of this structure, the engineering team conducted a site survey and then developed a master plan, determining how the dormitory could continue with all of its uses. However, the design team was absolutely committed to preserving the beautiful, three-story open cascading stairs. Another key objective was to preserve open sight lines between the assembly hall and the residential area.
The design solution was to strategically place fire-rated door assemblies. The team specified pocket doors and doors designed with magnetic hold-opens. The exit arrangement at the third floor was also modified. The recommendations were presented to code officials to demonstrate how this approach would satisfy fire-safety concerns.
Smoke-free space for youth
Another interesting project in the San Francisco Bay area is a children's science museum called the 'Exploratorium' located in the Palace of Fine Arts, which was built in 1914 for the World's Fair Exposition. This 'temporary structure' still stands 85 years later, an unlikely survivor in an earthquake-prone region. Approximately two-thirds of the mammoth 122,000-square-foot structure is used for the museum space. The current project, led by San Francisco architects Esherick Homsey Dodge & Davis, is to add 40,000 square feet more space at the mezzanine level, which is currently 19,000 square feet in size.
California's state historic building code called for installing an automatic sprinkler system throughout the building, but the project team wasn't sure this would be all that effective considering the Exploratorium's barn-like structure. Instead, engineers conducted a smoke-control analysis, which demonstrated that if the facility utilized sprinkler protection in low-ceiling areas, the affected sections of the building could be evacuated in the event of a fire incident, while the remaining areas would remain tenable for the occupants.
At first, engineers thought they would need to install a mechanical smoke-removal system, but after conducting computer modeling, they concluded that by using only a passive fire-protection system-an early-warning smoke detection system-installing a mechanical smoke-removal system wouldn't be necessary. Substantial cost savings were realized by this decision.
Sleeping better than Washington
Enhancing the safety of historic structures has extended to the nation's historical areas as well. At the Colonial Williamsburg (Va.) Historical Area, for example, the Colonial Williamsburg Foundation is renovating a wide range of structures including the renowned Williamsburg Inn.
'You're not going to change the place, are you?' one startled guest asked the design team, which includes Boston-based Jung Brannen Associates and Hughes Associates, during a walk-through of the antique-filled inn last year. The patron's family had spent every Christmas at the inn for the past 25 years-a common occurrence for the facility, which was built in the '30s and has served as the park's premier-class hotel ever since.
The major renovation will restore the lobby and other common areas and reduce the total number of guest rooms-allowing for larger rooms and updated comforts. Initially, the inn faced a number of fire-safety issues, including open stairwells, nonconforming walls, ramp hazards and accessibility problems, as well as smoke-containment and egress challenges.
The designers devised a multifaceted solution including a sprinkler system that would be designed not to compromise the aesthetics of the building. This was accomplished by concealing sprinklers in the corridor and room ceilings. In addition, a complete-coverage, analog photoelectric smoke-detection system was recommended that would be connected to Colonial Williamsburg's security and fire-alarm monitoring center.
Passive fire-protection measures were also developed to maintain the open appearance and flow of the original design, while providing for the enhanced degree of safety needed. Open staircases were enclosed at the basement level, but left open between the first and second floors. On the second floor, one staircase was enclosed with fire-rated glass and further fitted with sprinkler protection. Some hallways were designated to have smoke doors that, when closed, would effectively convert the stairwell into a lobby-like enclosure. Last, a pocket fire door was installed to separate assembly occupancy areas from guest areas.
For occupant egress, a stairwell was added behind the building, but was positioned where it could be hidden by shrubbery.
All recommendations for the Inn were incorporated into a request for modification that was accepted by all parties, including the foundation, the architects and the building inspector.
Protecting cultural resources
From the perspective of those involved with the National Fire Protection Association's committees 909 and 914, which focus on the protection of cultural resources, a key goal is balancing the needs of safety and expectations for historic preservation. It is also important to involve people who speak the language of the building inspectors. While some architectural firms have these capabilities, the more complex the issues, the more important it is to access reliable outside resources: people who understand the importance of historical preservation, know the building codes intimately and deal with life-safety issues every day.
The payoff is threefold: Historic preservation is not compromised. Less time and rework is spent on the approval process. And the solutions recommended and approved are often more cost-effective than what was originally envisioned.
Fireproofing Historic Retrofits
Fire-rated doors and fire walls . A fundamental part of fire safety, fire-rated doors and walls can be made to look like their historic counterparts. At Bancroft Hall, fire-rated partitions and doors help handle large occupancy loads and limited egress points. At Toyon, fire-rated pocket doors and doors with magnetic hold-opens preserve a three-story open stairwell to maintain lines of sight between assembly and dormitory zones. Pocket fire doors are installed at the Williamsburg Inn to separate assembly occupancy areas from guest areas. Other hallways at the hotel are fitted with smoke doors that, when closed, convert the stairwell into a small lobby enclosure.
Smoke-modeling analyses . Conducted for Bancroft Hall and the Exploratorium, these computer-modeling techniques help determine the feasibility of egress. At the Exploratorium, for example, a smoke-control analysis showed that sprinklers in low-ceiling areas would allow evacuation and that other areas would remain tenable.
Interior stairwells . At Bancroft Hall, interior stairwells help solve egress problems without altering the building's exterior appearance. Fire-rated glass partitions inside the Williamsburg Inn enclose an existing internal staircase that is also fitted with sprinkler protection on the second floor.
Early-warning smoke detection . In place of mechanical smoke removal, the Exploratorium benefits from a passive smoke-detection system designed to allow occupants enough time to exit in the event of an emergency. At the Williamsburg Inn, an analog photoelectric smoke-detection system offering complete coverage is employed, connected to the main command center for the entire campus.
Concealed fire sprinklers . Another effective product for historic retrofits, concealed sprinklers are installed in corridors and room ceilings at the Williamsburg Inn.